This invention is related to the cable treatments and in particular, to a method and apparatus for treating non-circular cables with a lubricant or rust inhibitor at high pressure.
Cables used in marine and land based applications are bundles of organized metal wires that provide strength in tensile loading applications. These cables are used on many applications seen every day just driving down the highway. Cranes used to lift cargo, draglines used in digging, suspension bridges, guy wires on antenna systems and building elevators are a few land based examples.
These examples also pertain to use offshore with the addition of mooring cables used to anchor floating systems to the ocean floor and umbilical systems used to tow underwater scientific packages behind ships. There are many other applications, but this list demonstrates the broad range of cable usage in the world today.
All of these cables are subject to corrosion with time. In offshore applications, this time is greatly reduced due to the salt water""s ability to corrode metals at an accelerated rate. There are several techniques currently used to fight the corrosion problems of both land based and marine applications. One such technique is the use of galvanized cable. The benefit of using galvanized cable is that the galvanizing material, molten zinc, is applied to the individual wires during the manufacture of the cable, resulting in a relatively minor cost impact. The galvanic coating process results in a relatively maintenance free cable, cable life is substantially extended, and the coating is relatively inexpensive. The negative aspects of the galvanic process are a reduction in the cable capacity for a given diameter of wire as the high strength wire has to be processed at a reduced diameter to allow for the additional zinc build-up during galvanizing (the change in diameter is squared in stress calculations, resulting in a significant impact on ultimate cable strength), cable system diameter must increase for the same load rating resulting in increase in all components the cable rolls across and is stored on, yielding a concomitant increase in overall system weight.
Thus, the relatively inexpensive galvanizing ultimately results in a significant cost increase to the total system, in salt water applications, break down of the zinc occurs fairly rapidly, and once the galvanizing is consumed by the salt water the cable must be replaced fairly quickly.
An alternative technique is the application of manually applied rust inhibitors. Use of rust inhibiting materials protects non-galvanized as well as galvanized cables, extends the life of galvanized and non-galvanized cables, can be reapplied as needed, and can be applied for the first time during the manufacturing of the cable. Detriments inherent in the use of such materials is that their application is messy, uniform application is extremely difficult, getting the inhibitor to penetrate to the core of the cable is very difficult with the high viscosity styles of inhibitors, service life is short with the brush-on low viscosity styles of inhibitors, and saltwater washes out the inhibitor with time.
U.S. Pat. No. 4,862,996 discloses a process wherein a liquid is applied to a wire rope by passing the rope through an elongated casing in which liquid is sprayed against the rope, excess liquid being discharged through annular grooves containing discharge openings upstream and downstream of the liquid inlet. Air is blown against the rope upstream and downstream of the annular grooves and discharge openings for causing the liquid to be discharged through such openings and not through the ends of the casing.
U.S. Pat. No. 5,333,704 discloses a device wherein a lubricant is applied to a lubrication point by moving an emitter in a first portion of a movement path through lubricant in a reservoir and then moving the emitter through a second portion of the movement path. The emitter is loaded with lubricant in the first portion of the movement path and is drained from a drain port during the second portion of the movement path. The lubricant drained from the emitter is distributed to the lubrication point. A distribution device may be positioned below the emitter to collect the lubricant drained from the emitter and to distribute the collected lubricant to a lubrication point or position other than a position below the emitter during the second portion of the movement path.
U.S. Pat. No. 4,063,617 provides an apparatus wherein a cable is passed through a lubricant filled chamber comprising an open housing and first and second flexible, annular discs each having radial slits along its inner circumference. A third flexible annular disc adjacent to said second disc includes radial slits on its inner circumference rotatably displaced from said second disc slits. The inner circumferences of the discs deformably engage the cable whereby lubricant beads are deposited at the second disc, which beads are uniformly spread by the deformably engaged sections of the third disc.
U.S. Pat. No. 5,107,961 provides a fixture facilitating the lubrication of cables including a housing having a clamping portion and a resilient insert to receive and capture the elongate cable and the end of the cable sheath, the compressible material being clamped around these portions. A valved lubricant aperture is provided in the fixture for introducing lubricant under pressure to the cable sheath while preventing blowback of the pressurized lubricant. The compressible insert in the fixture is designed to be captured in the base of one portion of the fixture and at another point in the moving portion of the fixture to allow it to be opened and closed for insertion and removal of the cable and sheath.
U.S. Pat. No. 4,422,529 teaches a method of lubricating steel cable wherein the steel cable is drawn through a chamber containing lubricant under pressure. The chamber has an outlet and an inlet lined with rubber sleeves through which the cable passes. A liquid lubricant is utilized, preferably a lubricating oil, which is supplied to the chamber by means of a pump having a high delivery pressure, minimum 20 bar and preferably above 40 bar, but with a relatively small delivery capacity. The rate of passage for the steel cable through the chamber is adapted such that the hollow spaces in the steel cable absorb the supplied oil to such an extent that oil leakage is avoided. The apparatus for carrying out the method comprises a chamber for lubricant under pressure, having an inlet and an outlet for the steel cable. A supply hose for lubricant leads to the chamber, and a pressure pump ensures pressure in the lubricant. The pump is a suction pump which can deliver a pressure of at least 20 bar, preferably above 40 bar, but has a small delivery capacity.
U.S. Pat. No. 4,336,866 is drawn to a wire rope lubricator cleaner for applying to a wire cable a lubricant cleaner, and removing from the wire cable excess lubricant cleaner so as to lubricate and clean the wire cable. A lubrication canister removably coupled to a rectangular shaped frame assembly applies the lubricant cleaner to the wire cable. A die rotatably mounted on an upper slide assembly of the rectangular shaped frame removes the excess lubricant from the cable and cleans the wire cable.
U.S. Pat. No. 3,951,235 is drawn to a greasing device for cables comprising at least one hollow body having walls defining an inner chamber adapted to be filled with a predetermined quantity of a lubricating material having a relatively high coefficient of viscosity, and a predetermined pressure. At least one pair of apertures are provided through said walls for a cable to be greased to extend therethrough and across said inner chamber so as to come into contact with said lubricating material inside said chamber; the size of said apertures being such that a predetermined clearance is present between the periphery of each aperture and the surface of the cable when the latter is mounted through the greasing device. A weighted member travels through the chamber housing, while acting on the grease therein, to force the grease toward the cable passing through the housing and toward the apertures in the housing through which the cable passes.
U.S. Pat. No. 4,498,558 teaches a lubricating device which is provided for greasing wire ropes and cables comprising a diametrically split housing with clamps to close the housing about the cable. Within the housing is a diametrically split core body of hard elastomeric material having an axial bore through which the cable travels axially. At the center of the core body is an internal cavity through which the cable passes and which is kept supplied with grease under pressure. Toward its ends the core body has two further internal cavities through which the cable passes, which serve to collect surplus grease. Between and beyond the grease supply and collection cavities, the axial bore of the core body is profiled so that each length of it has the form of an internal triangular section or Vee threaded screw thread; except that the directions of the screw thread are mutually reversed in the two halves of the split core body. The minimum diameter of the screw threads is substantially equal to the cable diameter so that sealing contact occurs between the cable and the thread peaks. At its ends, the housing is fitted with scraper plates having central holes, through which the cable passes, of substantially the same diameter as the cable.
What is lacking in the prior art is a cable treatment device for use in cleaning, lubricating or coating of a cable that is adapted to the follow the natural helix of the cable to provide high pressure treatment of a cleaner, lubricant or high viscosity inhibitor with minimal fluid loss by extending the life of the sealing mechanism and minimum wear to the cable.
Currently, low viscosity brush on inhibitors are used on cables with non-circular cross-sections and the high viscosity inhibitors can be applied to circular cross-section cables with a pressure applicator. The present invention provides a pressure applicator having a configuration and seal design which enables sufficient pressure generation to provide complete penetration of the lubricant within the section of cable being treated. The design provided by the instant invention not only functions with cables having a non-circular cross-section, but it also provides a superior sealing for treatment of circular cables.
This design provides a significant benefit by insuring application of a superior high viscosity inhibitor to all cables as long as physical space allows. The rotation capability reduces seal wear on the circular cross section cables by following the helix formed by the outer layer wire.
Accordingly, it is an objective of the instant invention to provide a rotary cable treatment assembly to coat a cable with either a pressurized lubricant or fluid rust inhibitor.
It is a further objective of the instant invention to provide a lubricator capable of applying sufficient pressure to impregnate the entirety of the cable""s cross section.
It is yet another objective of the instant invention to provide a rotary cable lubricator having a seal structure adapted to follow the cable geometry while experiencing minimal wear and simultaneously retaining maximum pressure.
Other objectives and advantages of this invention will become apparent from the following description taken in conjunction with the accompanying drawings wherein are set forth, by way of illustration and example, certain embodiments of this invention. The drawings constitute a part of this specification and include exemplary embodiments of the present invention and illustrate various objects and features thereof.